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Effect of spin coating on electrical properties of MXene films deposited from non-aqueous solvents
Gutsul, O. ; Szabó, Ondrej ; Pfeifer, R. ; Sasitharan, K. ; Jackivová, Rajisa ; Slobodyan, V. ; Kromka, Alexander ; Rezek, B.
We investigated the effect of spin coating parameters on the electrical properties of Ti3C2 MXene thin films deposited from non-aqueous suspensions in N,N-dimethyl formamide (DMF) and N-methyl-2-pyrrolidone (NMP) on gold interdigitated electrodes (IDE). The electrical properties of DMF-MXenes and NMP-MXenes films are characterized by impedance spectroscopy (4 Hz - 8 MHz at 1 V) using gold IDE with 25 µm gap. The electrical conductivity of MXene films decreases with increasing spin coating speed from 300 to 900 rpm. The series resistance (Rs) and double layer capacitance remain similar (Cdl). In all cases, MXenes deposited from DMF have five orders of magnitude higher electrical conductivity (lower Rct) than MXene films deposited from NMP. It is correlated with the thin film morphology obtained by scanning electron microscopy (SEM). These findings can be useful for possible application of MXenes as charge transport layers in hybrid photovoltaic devices.
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Dynamic in-situ experiments utilizing probe microscopy
Patočka, Marek ; Frank, Otakar (oponent) ; Kolíbal, Miroslav (vedoucí práce)
In this thesis, several case-studies of dynamic in-situ scanning probe microscopy experiments are presented. First, the electrodeposition of lithium in a solid state battery without a positive electrode is investigated. This experiment is followed by a similar measurement in which MXene particles are employed as a positive electrode material. The second part of the thesis deals with the graphene-on-liquid-metal system. An investigation into the presence of a meniscus surrounding the graphene flakes is presented.
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Designing novel catalyst loaded electrode materials towards electrochemical sensing to energy applications
Kandambath Padinjareveetil, Akshay Kumar ; Escarpa, Alberto (oponent) ; Vidal, Salvador Pané (oponent) ; Pumera, Martin (vedoucí práce)
The exponential increase in energy crises along with rising health issues is causing enormous risks to the survival of human life on Earth. Immense research is being undertaken currently to find an ideal solution to overcome these global challenges. Employing electrochemical energy technologies are thus in high demand to mitigate the growing energy requirements along with fabricating newer electrocatalysts that are cheap, efficient, and durable for utilization of such devices for large-scale commercial applications. Although several catalyst materials are being periodically studied, there is a need for more advanced studies in this direction. In the present study, newer catalyst fabrication techniques are introduced to develop application-specific catalysts for hydrogen and ammonia production. Also, with the broadening scope of the 3D-printing technology in recent times, electrocatalysts fabrication via this technology towards electrocatalytic applications such as hydrogen production, ammonia synthesis, and carbon dioxide mitigation are discussed in detail. In addition to catalysis, the current thesis also evaluates the potential possibilities of using 3D-printing technology for healthcare applications such as electrochemical sensors and emergency applications. In short, the thesis aims to provide an understanding of the recent advancements in electrocatalyst fabrications along with providing a fundamental foundation in designing, and engineering active electrode materials for energy conversion and electrochemical sensing applications.
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Radical-based tuning the surface functionality of MXene
Olshtrem, A. ; Chertopalov, Sergii ; Guselnikova, O. ; Švorčík, V. ; Lyutakov, O.
The family of MAX phases and their derivative MXenes are continuously growing in terms of both crystalline and composition varieties. MXenes are a new family of two-dimensional (2D) transition metal carbides, carbonitrides and nitrides, with a general formula Mn+1AXn, where n = 1–3, M denotes a transition metal, A is an element such as aluminum or silicon, and X is either carbon or nitrogen. Considering the various elemental composition possibilities, surface functional tunability, various magnetic orders, and large spin–orbit coupling, MXene can truly be considered as multifunctional materials that can be used to realize highly correlated phenomena.
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